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Thin films prepared in RF glow discharge and their physico-chemical properties
Bránecký, Martin ; Boušek, Jaroslav (referee) ; Čech, Vladimír (advisor)
Theoretical part of this master thesis was focused on literature recherché dealing with the formation of thin films, plasma, plasma analyses using mass spectrometry and plasma polymerization. Further, this section describes the analysis of thin films using optical methods such as spectroscopic ellipsometry and FT-IR spectrometry. Experimental part describes the materials which are used for the preparation of thin films as well as a description of the equipment for preparation of thin films using a technology of plasma-enhanced chemical vapor deposition (PE-CVD). Control of deposition conditions and monitoring of plasma with its products result in high reproducibility of thin films. The last part of the thesis describes the results of measurement of the first group of samples and their ellipsometric, mass spectrometry and FT-IR evaluation with respect to the deposition conditions.
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Study of plasma species by mass spectroscopy
Bureš, Michal ; Čáslavský, Josef (referee) ; Čech, Vladimír (advisor)
Plasma polymer films of tetravinylsilane and mixture of tetravinylsilane and oxygen gas were deposited on silicon wafers. Oxygen gas was mixed in tetravinylsilane to improve the compatibility of thin films on glass substrates. Mass spectroscopy was employed during the cleaning of the deposition chamber to check residual gases and process gases, during plasma deposition to monitor neutral plasma species and to follow plasma stability.
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Study of organosilicone fragmentation in plasma
Sahánková, Hana ; Studýnka, Jan (referee) ; Krčma, František (advisor)
This Bachelor Thesis deals on the study of organosilicone monomers in plasma. The dimethylphenylsilane (DMPS) was chosen as the organosilicone example. The theoretical part gives basic overview of plasmachemical processes and technologies used in present world. Some part is reserved for the description of plasma diagnostic basic methods as optical emission spectroscopy and mass spectroscopy. The experimental part is constituted from two different experiments. The first one was done as model experiment of DMPS fragmentation by electron beam of exact energy and it was completed at Faculty of Mathematics, Physics and Informatics in Bratislava. Results of these experiments brought a set of electron energies needed for the creation of various ionic fragments from the original molecule as well as the cross sections for their creation. The second part of the experiments was carried out under the inductively coupled RF low pressure plasma conditions during the deposition of DMPS based thin films. The plasma was monitored by optical emission spectroscopy at different discharge power. Various species were identified in the spectra. The calculation of plasma parameters and their comparision with the model experiment data will be subjects of the further work.
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Diagnostics of thin layer deposition using tetravinylsilane monomer
Flamíková, Kristýna ; Dvořák,, Pavel (referee) ; Krčma, František (advisor)
The aim of this work is plasma diagnostic during the deposition of thin films based on organosilicone compounds. These layers have a wide range of applications mainly as protective coatings or intermediate phase in composites reinforced by glass fibers. The theoretical part of this work gives a basic fundaments of optical emission spectroscopy and mass spectroscopy and describes procedures for rotational, vibrational, and electron temperature calculations. The RF capacitive coupled discharge in configuration with planar electrodes was used with tetravinylsilane (TVS) organosilicone monomer in this study. The optical emission spectroscopy and mass spectroscopy were applied for the plasma diagnostics. The deposition process was carried out in continuous regime with applied power of 20, 25, 40, 50, 60, and 70 W, some experiments were done also in pulsed regime with duty cycle 1:1, 1:4 and 1:9 at fixed power of 50 W and 10 W when discharge was on. The atomic lines of hydrogen Balmer series and many rotational lines of molecular hydrogen were identified in the spectra. Besides them, the molecular bands of SiH, CH and C2 species were observed. The rotational temperature calculated from 0-0 CH band was in the range of 600 – 1000 K depending on the discharge conditions. The electron temperature in the range of 3600-7500 K was calculated from hydrogen atomic lines. In situ mass spectra collected simultaneously with optical emission spectra showed TVS monomer fragmentation increase with the increase of applied power in continuous regime. This result well correlated with OES in case of CH radical and hydrogen species, the other particles were mainly non-measurable by emission spectroscopy. The same results were also obtained with respect to the duty cycle parameter. The presented results clearly demonstrated the increase of monomer fragmentation with the increase of mean applied discharge power. Determination of prepared layer properties is a subject of other works and their relation to the plasma parameters will be a subject of further studies.
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Methods of hydrogen charging of steels for an experimental purposes
Gordiak, Michal ; Němec, Karel (referee) ; Válka, Libor (advisor)
Bachelor thesis deals with the issue of hydrogen charging. The first part of the thesis describes individual methods, by which experimental materials are charged with hydrogen today. There are also included results of hydrogen charging experiments available in literature, achieved by described methods. The second part of the thesis is focused on techniques for analyzing hydrogen in metals and measuring surface or overall concentration of hydrogen in specimens.
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Secondary metabolites and antimicrobial effects of neotropical members of the genus Hermatomyces
Ježková, Tereza ; Koukol, Ondřej (advisor) ; Žabka, Martin (referee)
Species of the genus Hermatomyces (Pleosporales) saprotrophs on wood and litter in the tropics. Since the secondary metabolites of this genus have not been investigated so far, this thesis focuses on them. In this thesis, the antifungal properties of the genus Hermatomyces were verified by pairing experiments on agar plates and by testing the minimum inhibitory concentrations of extracts obtained from fungal biomass. The extract of one selected strain, H. reticulatus CCF 5893, was separated by preparative HPLC. The selected biologically active fractions were purified and the chemical structure of the separated compounds was determined by nuclear magnetic resonance analysis and X-ray crystallography. Two compounds were found in this species: palmarumycins C2 and C12, which have antifungal properties. Furthermore, a total of 25 Hermatomyces strains were compared in terms of secondary metabolite production (by testing their minimum inhibitory concentrations and comparing HRMS data). Unique compounds were produced by H. megasporus, which also showed the highest antimicrobial activity of all species and is therefore the most suitable species for further study of antimicrobial compounds of this genus.
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Alternative synthesis of of 1-(diphenylphosphino)-1'-(N,N-dimethylaminomethyl)ferrocene
Zábranský, Martin ; Štěpnička, Petr (advisor) ; Vojtíšek, Pavel (referee)
An alternative, more straightforward and effective method for the preparation of 1- (diphenylphosphino)-1'-(N,N-dimethylaminomethyl)ferrocene was developed using 1-bromo- 1'-(diphenylphosphino)ferrocene as the starting material and Eschenmoser's salt as an aminomethylation agent. Purity of thus prepared phosphinoamine was verified by 1 H and 31 P NMR spectroscopy and by comparison of the data with those reported in the literature (M. E. Wright, Organometallics, 1990, 9, 853). The coordination chemistry of this compound was investigated in gold(I) complexes. Thus, chlorido[1-(diphenylphosphino)-1'-(N,N-dimethyl- aminomethyl)ferrocene]gold(I) complex was synthesized and converted to ill-defined [1- (diphenylphosphino)-1'-(N,N-dimethylaminomethyl)ferrocene]gold(I) perchlorate by halogen abstraction with AgClO4. Protonization of the nitrogen atom in both compounds with hydrogen chloride yielded the corresponding hydrochlorides. It was shown that 1- (diphenylphosphino)-1'-(N,N-dimethylaminomethyl)ferrocene is coordinated as a simple phosphine in the resulting complexes while its amine nitrogen is protonated. All these complexes were characterized by means of 1 H, 31 P and 13 C NMR spectroscopy, mass spectroscopy with electrospray ionisation, elemental analysis and by single-crystal X-ray diffraction analysis.
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Methods of hydrogen charging of steels for an experimental purposes
Gordiak, Michal ; Němec, Karel (referee) ; Válka, Libor (advisor)
Bachelor thesis deals with the issue of hydrogen charging. The first part of the thesis describes individual methods, by which experimental materials are charged with hydrogen today. There are also included results of hydrogen charging experiments available in literature, achieved by described methods. The second part of the thesis is focused on techniques for analyzing hydrogen in metals and measuring surface or overall concentration of hydrogen in specimens.
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Alternative synthesis of of 1-(diphenylphosphino)-1'-(N,N-dimethylaminomethyl)ferrocene
Zábranský, Martin ; Štěpnička, Petr (advisor) ; Vojtíšek, Pavel (referee)
An alternative, more straightforward and effective method for the preparation of 1- (diphenylphosphino)-1'-(N,N-dimethylaminomethyl)ferrocene was developed using 1-bromo- 1'-(diphenylphosphino)ferrocene as the starting material and Eschenmoser's salt as an aminomethylation agent. Purity of thus prepared phosphinoamine was verified by 1 H and 31 P NMR spectroscopy and by comparison of the data with those reported in the literature (M. E. Wright, Organometallics, 1990, 9, 853). The coordination chemistry of this compound was investigated in gold(I) complexes. Thus, chlorido[1-(diphenylphosphino)-1'-(N,N-dimethyl- aminomethyl)ferrocene]gold(I) complex was synthesized and converted to ill-defined [1- (diphenylphosphino)-1'-(N,N-dimethylaminomethyl)ferrocene]gold(I) perchlorate by halogen abstraction with AgClO4. Protonization of the nitrogen atom in both compounds with hydrogen chloride yielded the corresponding hydrochlorides. It was shown that 1- (diphenylphosphino)-1'-(N,N-dimethylaminomethyl)ferrocene is coordinated as a simple phosphine in the resulting complexes while its amine nitrogen is protonated. All these complexes were characterized by means of 1 H, 31 P and 13 C NMR spectroscopy, mass spectroscopy with electrospray ionisation, elemental analysis and by single-crystal X-ray diffraction analysis.
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Thin films prepared in RF glow discharge and their physico-chemical properties
Bránecký, Martin ; Boušek, Jaroslav (referee) ; Čech, Vladimír (advisor)
Theoretical part of this master thesis was focused on literature recherché dealing with the formation of thin films, plasma, plasma analyses using mass spectrometry and plasma polymerization. Further, this section describes the analysis of thin films using optical methods such as spectroscopic ellipsometry and FT-IR spectrometry. Experimental part describes the materials which are used for the preparation of thin films as well as a description of the equipment for preparation of thin films using a technology of plasma-enhanced chemical vapor deposition (PE-CVD). Control of deposition conditions and monitoring of plasma with its products result in high reproducibility of thin films. The last part of the thesis describes the results of measurement of the first group of samples and their ellipsometric, mass spectrometry and FT-IR evaluation with respect to the deposition conditions.
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